1. Field of the Invention:
This invention relates to compressor systems. More particularly, it relates to an apparatus for preventing surging in a pneumatic system for a turbo-compound compressor system including a rotary positive-displacement air compressor drivable by an internal combustion engine.
2. Description of the Prior Art:
A small, inexpensive and highly efficient turbo-compound compressor system which utilizes the exhaust gas energy of an internal combustion engine effectively is disclosed in Japanese Utility Model Application Laid-Open Publication No. 55-165926 published provisionally on Nov. 28, 1980. A pneumatic system for a rotary positive-displacement air compressor driven by an internal combustion engine having a turbocharger supercharges the engine and includes a booster compressor connected to a power recovery turbine disposed at the outlet of an expansion turbine in the turbocharger. The air discharged by the booster compressor is supplied to the rotary positive-displacement air compressor to increase the pressure of the air drawn thereinto.
More fundamental art relating to the turbo-compound compressor system includes a rotary air compressor system of the type disclosed in British Patent Specification No. 1 441 498.
These known turbo-compound compressor systems have the disadvantage of having a surging phenomenon in the pneumatic system when the rotary positive-displacement air compressor is in or close to the no-load state. Especially in the pneumatic system of Japanese Publication No. 55-165926, surging is very likely to occur in the booster compressor when the rotary positive-displacement air compressor is in or close to the no-load state.